lib: Prevent crash in getting label chunk

ldpd has this crash:

(gdb) bt
0  __pthread_kill_implementation (no_tid=0, signo=11, threadid=140329211443648) at ./nptl/pthread_kill.c:44
1  __pthread_kill_internal (signo=11, threadid=140329211443648) at ./nptl/pthread_kill.c:78
2  __GI___pthread_kill (threadid=140329211443648, signo=signo@entry=11) at ./nptl/pthread_kill.c:89
3  0x00007fa0f0642476 in __GI_raise (sig=11) at ../sysdeps/posix/raise.c:26
4  0x00007fa0f0b51944 in core_handler (signo=11, siginfo=0x7fff562810b0, context=0x7fff56280f80) at lib/sigevent.c:268
5  <signal handler called>
6  0x00007fa0f0b9534d in lm_get_label_chunk (zclient=0x0, keep=0 '\000', base=0, chunk_size=64, start=0x7fff56281bdc, end=0x7fff56281be0) at lib/zclient.c:3667
7  0x0000564e0d1c011e in lde_get_label_chunk () at ldpd/lde.c:2211
8  0x0000564e0d1c05f8 in lde_get_next_label () at ldpd/lde.c:2318
9  0x0000564e0d1bcb29 in lde_update_label (fn=0x564e16653050) at ldpd/lde.c:783
10 0x0000564e0d1c1fbe in lde_kernel_update (fec=0x7fff56281cb0) at ldpd/lde_lib.c:422
11 0x0000564e0d1b96c0 in l2vpn_pw_init (pw=0x564e165d1fa0) at ldpd/l2vpn.c:242
12 0x0000564e0d1b2d32 in merge_l2vpn (xconf=0x564e166424f0, l2vpn=0x564e166160a0, xl=0x564e165eabb0) at ldpd/ldpd.c:1883
13 0x0000564e0d1b28ea in merge_l2vpns (conf=0x564e166424f0, xconf=0x564e16653650) at ldpd/ldpd.c:1813
14 0x0000564e0d1b1244 in merge_config (conf=0x564e166424f0, xconf=0x564e16653650) at ldpd/ldpd.c:1321
15 0x0000564e0d1bc485 in lde_dispatch_parent (thread=0x7fff56282060) at ldpd/lde.c:611
16 0x00007fa0f0b6cebc in event_call (thread=0x7fff56282060) at lib/event.c:2019
17 0x0000564e0d1baee7 in lde () at ldpd/lde.c:155
18 0x0000564e0d1ae4b8 in main (argc=0, argv=0x7fff56282298) at ldpd/ldpd.c:312
(gdb)

Since it is possible to be asking for label data before the zclient has
been connected, let's just return -1 in the case where zclient is not
initialized yet either, since this is effectively the same thing as
the sock being < 0.

Signed-off-by: Donald Sharp <sharpd@nvidia.com>

diff --git a/lib/zclient.c b/lib/zclient.c
index 5deea8f0cfa8fcf53551bb8cf2687ac2867b1028..532771cb934df0b025b5752633a2d49da9be1580 100644 (file)
--- a/lib/zclient.c
+++ b/lib/zclient.c
@@ -3664,7 +3664,7 @@ int lm_get_label_chunk(struct zclient *zclient, uint8_t keep, uint32_t base,
        if (zclient_debug)
                zlog_debug("Getting Label Chunk");
 
-       if (zclient->sock < 0)
+       if (!zclient || zclient->sock < 0)
                return -1;
 
        /* send request */